In recent years, infilled artificial turf has become increasingly more popular in the United States as a playing surface for organized sports, particularly football. A typical infilled artificial turf includes a horizontal backing, often called a primary, grasslike fibers extending upwardly from the backing, and particulate infill located on the backing and within and amongst the grasslike fibers. The infill supports the fibers in a generally upright position. Typically, the particulate infill material may include sand, crumb rubber, which may be ambiently or cryogenically ground, or a combination of sand and rubber. Other materials also may be used, such as materials considered to be more environmentally safe, such as water-repelling, non-compacting, and non-mounding beads of the type disclosed in U.S. Pat. No. 8,034,429.
A standard U.S. football field includes a number of conventional and widely recognized markings. These markings identify various places on the field, such as the goal line, the side lines, the yardlines, etc. The dimensions of all U.S. football fields are the same. That is, they are 100 yards (300 feet) long, i.e. between one goal line and the opposite goal line, and the widthwise dimension, i.e. from one sideline to the other sideline, is 53.3 yards (160 feet). There are also hash mark lines that extend the length of the field, with one hash mark line on each side. Generally, at least for college and high school football fields, the hash marks are wider than the span of the goal posts located at the rears of the opposing end zones.
The present invention relates to the numbering of the yardlines for such a field. More specifically, each side of the field bears a yardline number every 10 yards. This means that when viewed from the sideline, the yardline numbers appear as follows: 10, 20, 30, 40, 50, 40, 30, 20, 10. Also, on the side of the yardline number that is nearest to the closest goal line, the field typically shows one arrow, or small triangle.
Currently, when a typical infilled artificial turf football field is initially installed, there are no yardline numbers already in place. Instead, those parts of the field typically are green. On the other hand, the initially installed field will typically already include the sidelines, the end lines, the yardlines, and the goal lines.
One option for adding the yardline numbers to a football field would be to paint the turf, at the outset, at the specific locations where the yardline numbers are to be located. However, painted yardline numbers are susceptible to wearing away, and thereby require subsequent paint applications. Such subsequent paint applications can damage the artificial turf fibers, and may also present a health risk to athletes playing on the surface. In fact, one recent NFL preseason game had to be cancelled because of concerns related to painted portions of an artificial turf. For these and other reasons, it has become common to insert into an infilled artificial turf football field the separately produced, colored yardline numbers, as described below.
More particularly, according to the most common manner of adding the yardline numbers to a field, the manufacturer of the artificial turf typically sends to the field site a set of yardline numbers that are already permanently colored white, or some other non-green color designated for the yardline numbers. Each of these already-colored artificial turf yardline numbers then becomes placed at the proper location on the turf, pinned in the proper location, and then the correspondingly sized section of the initial turf residing below is cut and removed, leaving an empty section shaped like the number shape that was removed. Thereafter, each of the colored yardline numbers is secured in place within the initial turf, by adhering the underside edge portion of the yardline number to the adjacently located underlying edges of the initially installed turf, via an underlapped connector. This fills in the empty section where the turf has been cut and removed. In other words, the permanently colored yardline numbers are substituted for the cut-out portions of the initially laid artificial turf. The green cut-out portions, which have the same shapes as the corresponding yardline numbers, are not used.
In order to properly locate the colored yardline numbers in the correct position and orientation, the field installer will typically measure the proper distance from the sideline and/or the hash marker, and then extend a string, or line, along the length of the field. This longitudinal temporary line, along with the closest actual yardline, is then used to properly locate a specific yardline number template on the field. For example, to form the yardline number “10” the installer will first use a “1” template on the left side of the ten yardline, and then use a “0” template on the right side of the ten yardline, thereby to form the complete number “10” for the 10 yardline.
Because each of the number-specific templates has a size that must be larger than the size of the corresponding number, by necessity these templates are relatively large. For example, the numbers are typically 4′×6′, while the number “1” is 3′×6′, and the corresponding templates are typically about 7′ in length and about 6′ in width and have an opening that is specifically shaped to abut the entire outer edge of one particular number. Also, these templates are usually made of aluminum. This inherent size issue, and the composition of the templates, increases the time, the cost, and the inconvenience of numbering a football field.
With a number-specific template located in the correct place on the field, the field installer places the corresponding single digit yardline number within the opening of the template, and then pins the yardline number to the top of the initial installed turf and removes the template. This enables the installer to thereafter cut the in place turf that is located directly below the outer edge of the pinned down white (or neutral) yardline number. Once that cut portion of the initial field has been removed, the white (or neutral) yardline number can then be secured into place, typically by adhering, i.e. gluing, the colored yardline number to the adjacently located portion of the field, via a lapped underlying piece with adhesive on its upper surface, to secure to the bottom edges of the yardline number and the adjacently located sections of the initially installed turf.
According to this approach the field installer uses six different number specific templates to install a typical American football field, i.e. one for each of the digits 0, 1, 2, 3, 4, and 5. Moreover, for each yardline the correct colored yardline numbers need to be correctly matched up with the correct templates, i.e. a digit of 1 through 5 plus a 0. Eventually all six of the number specific templates are used at specific locations on the field. More specifically, each of the non-zero number templates is used twice, on diagonally opposite locations of the field, while the “0” template is used eighteen times.
Thus, the current state of the art with respect to adding the yardline numbers to a football field requires the installing crew to have and to maintain at least one complete set of the number-specific templates, i.e. at least six templates in total. Due to the need to travel to the field itself and store the templates when not in use, the templates generally get beaten up over time. Moreover, due to the carrying of the templates to multiple sites on the field during the numbering process, the use of multiple yardline numbering templates adds to the time, the cost, and the inconvenience of installing a football field.